This invention relates to a modular end-forming device, or end former, used to modify the geometry of the end of a tube. More particularly, the present invention relates to a modular device that can expand, reduce, or flare the ends of tubes having differing diameters and wall thicknesses such as those tubes used in air conditioning coils.
Often it is necessary to modify the geometry of an end of a tube to facilitate the creation of a joint such as a slip joint used to join two lengths of tubing. Similarly, it is often necessary to flare the end of a tube for use in a compression fitting. Tubes that are modified in these manners are typically thin-walled and made of a malleable material such as copper.
One of the problems which is encountered in the assembly of tube devices is the need to quickly and efficiently join tubes together, either when the unit is assembled in the field or when repairs are made. Even in factory assembly, coil units require tubes to be joined and this procedure needs to be accomplished as effectively and efficiently as possible.
Fluid pressure devices operated by hydraulic pressure or pneumatic pressure are known, particularly for expanding tubes such as those used in air conditioning coils and the like. Several hydraulic devices have been developed which are suitable for tightly gripping one end of an elongated tube while simultaneously delivering a tube expanding fluid. Among these are U.S. Pat. Nos. 3,505,846; 3,813,751, 3,962,769; and 4,189,162. None of these patents describe devices which are suitable for expanding the ends of tubes.
Other prior art devices which are used to expand the ends of tubes are devices which include a split finger means which is inserted in the tube. As the split fingers expand or flair out the end of the tube, material is squeezed between the fingers, leaving longitudinally extending ridges or raised portions. These raised portions of material cause several problems, both in obtaining a good junction and strong seal, and in requiring the use of much more silver solder or other sealing material.
U.S. Pat. No. 5,134,872, issued to Paul N. Ose and hereby incorporated by reference and commonly assigned herewith, discloses a device for expanding the inner diameter of tube ends having varying wall thicknesses. However, this device is capable of expanding a tube diameter only and is not capable of reducing a tube""s diameter or flaring the end of a tube.
Accordingly, it is an object of the present invention to provide a modular mechanism that utilizes interchangeable modules and tooling to effect the expansion, reduction, and flaring of tube ends. Another object of this invention is provide a modular mechanism that may modify tubes of various diameters and wall thicknesses.
These and other objectives and advantages of the invention will appear more fully from the following description, made in conjunction with the accompanying drawings wherein like reference characters refer to the same or similar parts throughout the several views.
A modular endformer according the present invention is capable of modifying a thin walled malleable tube by reducing the diameter thereof, expanding the diameter thereof, and by flaring or belling the end of the tube. In achieving this functionality, the endformer of the present invention is constructed and arranged to utilize common structures to alternatively actuate and operate an expanding tool, a reducing tool, and a flaring tool. As can be appreciated, the dimensions of the expansion tool, reducing tool and flaring tool may be varied to accommodate variously sized tubes.
The endformer of the present invention essentially comprises a body having a piston structure and a collet mechanism slidably disposed therein. The body has first and second inlet structures for a source of fluid under pressure. The body also has a tube-receiving end that allows a tube to be inserted therein.
The piston structure is longitudinally movable within the body between a first, retracted position and a second, extended position. The piston structure is moved to its first position by the introduction of a pressurized fluid into the first inlet structure, and is moved to its second position by introducing the pressurized fluid into the second inlet structure. The piston structure has coupled thereto an adjustment mechanism that provides for controlling the distance traveled by the piston structure between its first and second positions. The piston structure and adjustment mechanisms are constructed and arranged to actuate one of the aforementioned expanding tool, reducing tool, and flaring tool.
The collet mechanism is disposed within the body adjacent the tube receiving end thereof and engages and clamps a tube end within the body. The collet mechanism is arranged such that the tube end is engaged at a location spaced apart from the end of the tube. The collet mechanism is actuated to grasp the tube by the piston structure when pressurized fluid is introduced into the first inlet structure and actuated to release the tube by the pressurized fluid introduced into the body by the second inlet structure.
Preferably, the body of the endformer will comprise a first half and a second half with the piston structure of the endformer being disposed substantially within the first half of the endformer and the collet mechanism being disposed substantially within the second half of the end former.
The piston structure of the present invention essentially comprises a primary piston that is slidably received within a bore formed in an actuator piston that is itself slidably received within the body of the endformer. The primary piston moves longitudinally within the actuator piston between a first position and a second position under the influence of pressurized fluids introduced through the first and second inlet structures, respectively. The primary piston actuates the expanding tool as the primary piston moves from its first position to its second position. The actuator piston simultaneously actuates the collet mechanism so that the collet mechanism will grasp and hold the tube as the expanding tool engages the tube.
The expanding tool used with the present invention comprises a sizing mandrel coupled to the primary piston and a forming insert disposed within the body generally adjacent the tube receiving end thereof. The forming insert has an interior bore of a predetermined size formed therethrough that is sized to receive therein an end of the tube that will be modified. The sizing mandrel is arranged to be inserted into the tube end that is disposed within the forming insert as the primary piston moves from its first, retracted, position to its second, extended position, thereby expanding the diameter of the tube end to that of the forming insert.
The reduction tool of the endformer of the present invention comprises a forming die and a removal shoulder that are coupled to the piston structure of the endformer. The forming die is operatively coupled to the end of the primary piston and the removal shoulder is coupled to the end of an adjusting mechanism that is itself operatively coupled to the primary piston independent of the forming die. The forming die has an interior tapered bore of a predetermined size and shape that when addressed to the end of a tube received within the body of the endformer, will reduce the outer diameter thereof. The forming die is actuated into contact with the end of a tube as the primary piston moves from its first position to its second position. As the primary piston moves back to its first, retracted position from its second, extended position, the removal shoulder acts to push a tube out of the tapered bore of the forming die as the forming die moves past the removing shoulder.
The flaring tool that is used with the endformer of the present invention comprises a flaring die that is coupled to the piston structure. The flaring die has a frustoconical surface having a predetermined angle that is constructed and arranged to engage the end of a tube received within the tube receiving end of the body as the piston structure moves from a first retracted position to a second extended position. When it operatively addresses the end of the tube, the frustoconical surface of the flaring die acts to flare out the end of the tube.
The collet mechanism of the endformer of the present invention essentially comprises a plurality of collet jaws that are operatively coupled to the piston structure of the endformer such that the collet jaws may travel longitudinally therewith. The collet jaws are further constructed and arranged to move in a radial direction with regard to the piston structure so as to permit the collet jaws to come into clamping contact with a tube end inserted into the tube receiving end of the body of the endformer. The collet mechanism may be used with each of the expanding tool, reducing tool, and flaring tool.
A preferred embodiment of the collet mechanism of the present invention comprises a collet actuator, a return collet and a plurality of collet jaws. The collet actuator is slidably disposed within a bore formed through a first section of the endformer. The return collar is also slidably disposed within the bore formed through the first section of the endformer and is coupled to the collet actuator so as to move therewith. The collet jaws are operatively coupled to the collet actuator and are constructed and arranged to move longitudinally with the collet actuator and to also move radially with respect to the collet actuator. The collet jaws of the endformer move radially inwardly so as to clamp a tube received within the body of the endformer when the collet jaws are brought into contact with an inner surface of the body of the endformer. This occurs as the collet mechanism moves from its first, retracted position, to its second, extended position.